A storm surge is often the most deadly part of a hurricane or tropical cyclone. Storm surges produce abnormally high tides that lead to flooding — and lack of understanding about the risk of storm surges prevents many in coastal communities from evacuating in time.
[Read more: What is a Storm Surge and What Causes It?]
Storm surges have a range of short-term and long-term impacts on coastal communities. A storm surge can render immediate damage, and also make coastal communities more vulnerable to future storms. Here’s why we should be taking storm surges more seriously — and how to prepare for stronger, climate change-fueled storm surges of the future.
Storm surges: immediate impact
Storm surges are frequently underestimated by coastal communities, which is one of the reasons why they are so deadly. More than 85% of US deaths from hurricanes and tropical storms are from water, not wind; water that’s mostly produced by the storm surge. In fact, roughly half of all U.S. deaths from tropical cyclones are due to the storm surge. Hurricane Katrina caused at least 1500 deaths directly or indirectly resulting from the storm surge.
Storm surges can cost billions of dollars in damage and devastate communities that are even dozens of miles inland. Hurricane Ike, for instance, was a Category 2 hurricane in 2008 that caused storm surges 15 - 20 feet above normal tide levels, leading to property damage estimated at nearly $25 billion.
[Read more: How To Plan Ahead For Rougher And More Dangerous Coastal Storm Surges]
How do storm surges cause so much devastation? Storm surges dump a massive amount of water on land — water that weighs approximately 1,700 lbs per cubic yard. This causes the destruction of property, as well as the erosion of beaches and damage to coastal habitats. If there’s a river or lake near the coast, inland flooding can also damage the foundations of infrastructure such as roads, bridges, and pipelines.
Storm surges: long-term impact
The immediate aftermath of these events can be eclipsed by the lasting damages to human infrastructure they often cause.
Early research efforts to quantify and analyze the long-term impact of hazardous storm surges show tangible shifts in human movement. IPCC estimates suggest that around 250 million people globally are vulnerable to storm surge events every year. These coastal communities are under increasing threat as storms intensify due to climate change. As a result, the study found more people are moving away from coastal areas at risk for flooding.
“This effect is especially large for low elevation coastal zones, while for non low elevation coastal areas we find no effect. The same pattern can be found for developing and developed countries, but the shrinking of the population is 39 percent larger in developing countries,” wrote the researcher, Sven Kunze.
Experts are starting to see the beginning of large-scale migration movements away from at-risk areas. Termed by some media outlets as “The Great Climate Migration,” it’s evident the coastal communities may no longer be “coastal” in the near future.
Scientists have tried to model what the storm surges of the future — those impacted by climate change — might look like. Because so many factors play a role in the size and intensity of a storm surge, researchers used data from 21 storms that impacted the Gulf of Mexico and Atlantic Coasts of the continental U.S. from 2000 to 2013 for their simulation. The results showed the volume of inundation increases for 14 storms; the average change for all storms is +36%. The extent of inundation increases for 13 storms, and the average change for all storms is +25%. By the end of the century, the team expects hurricanes to produce larger storm surges in concentrated areas, suggesting that the impacts of their intensification will be felt disproportionately.
Preparing for stronger surges
Amplified by an atmosphere full of greenhouse gases, surges forced by hurricanes have grown in magnitude and severity in recent years. People living in coastal areas remain most vulnerable to these extreme tidal events. However, displacement is not a realistic option for most. Understanding the degree to which storm surges are worsening can help coastal communities better prepare, make necessary upgrades to infrastructure, and build natural barriers to try to mitigate the short-term impact of these surges.
Measurements from Sofar Ocean's Smart Mooring are used to develop storm warning systems that provide coastal communities with early notice of rogue waves. Smart Mooring includes a pressure sensor to measure water level and capture storm surges. Experts can continually take the pulse of the sea state, detect incoming storms and get ahead of flood risks. Strategies and decisions can then be made according to data patterns or irregularities, rather than guesswork.
Individually, Sofar Ocean's systems can optimize hurricane forecasts, improve flood maps, hasten hazard warnings, and validate sea-level rise models. To learn more about our tools, visit our Marine Sensing Devices page.